Wrist/arm control

I've come to the realization that one of the things that I suck at is wrist control. One of the main reasons people dominate me is because they can keep control of my wrists and thereby my arms, taking away many of my potential attacks and defenses. My instructor has shown me a sort of quasi-escape from under wrist control where I turn my wrist out and grab my opponent's wrist, but this seems to be pretty low-percentage from my experience. I feel like a dumbass asking this, but are there subtleties in setting up a wrist-out that I have to pay attention to? Are there any drills I can do on my own to improve my wrist control?

That thing your instructor is telling to do works. It is really simple. Do you feel like your not strong enough? That is actually really high percentage like 80% for me. You need to use your whole arm. Make a big circle with your arm while simultaneously rotating your wrist.

Also play with your arms close to your body and your elbows tucked in until you are ready to grip up. Don't just leave your arms hanging out there.

You need to train them with a partner until your wrists are big and hairy ...
then you will have great anti-grab-my-wrist power and all the aikidoka will respect you!

When someone grabs my wrist I don't give a damn, that's their problem : they can't pull me or push me anywhere, I can rotate my wrist in their grasp if I want. I can escape when I want, meanwhile they have their hand busy instead of doing something useful like mashing me in the nose or getting my collar or sleeve. I speak from an ignorance of judo though ... but I mostly see decent judo executed from gi-grabs, ...

As for techniques ;
elbow down, fingers up the inside : grip is broken on inside of wrist line.
elbow down, hand-mouth up outside : get a nasty nikky-type thing on or they let go.
Sudden press then snatch : grip is broken or balance is broken, they choose.

Dude a simple trick that works everytime for me, is to rotate my wrist towards my opponents tumb. Always towards the tumb! Try it out with someone you know. Your opponent has to be mighty strong for it not to work. I'm a semi skinny guy and everyone I know can get a good grip all around my wrist, so I had to learn this trick so not to being controlled too easily. It is your entire forearm against your opponents tumb. You can even try it yourself. And just keep doing it everytime he graps your wrist.

One workout that improved my grabbing strength and forearm strength was wrapping a towell around a pull-up bar so that the two ends hung down. Grab the two ends and do pull ups till you can't do anymore.
Get some hand-grippers and put them in your car, do one hand on the way to work, one hand on the way back, or just alternate every light.
As for wrist control, slide your hand down one of your wrists till it hits the back of your hand, now you have a small handle that can prevent someone pulling out faster.